package jhsys.hithink.basepage.flingview;

import android.content.Context;
import android.graphics.Camera;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.os.Handler;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.widget.Scroller;

public class FlingLayout extends ViewGroup {
	private static final String TAG = "FlingLayout";
	// 用于滑动的类
	private Scroller mScroller;
	// 用来跟踪触摸速度的类
	private VelocityTracker mVelocityTracker;
	// 当前的屏幕视图
	private int mCurScreen;
	// 默认的显示视图
	private int mDefaultScreen = 0;
	// 无事件的状态
	private static final int TOUCH_STATE_REST = 0;
	// 处于拖动的状态
	private static final int TOUCH_STATE_SCROLLING = 1;
	// 滑动的速度
	private static final int SNAP_VELOCITY = 600;

	private int mTouchState = TOUCH_STATE_REST;
	private int mTouchSlop; // 溢出
	private float mLastMotionX;
	private float mLastMotionY;

	// 用于更新当前在第几页
	private Handler mHandler;

	// 用来处理立体效果的类
	private Camera mCamera;
	private Matrix mMatrix;
	// 旋转的角度
	private float angle = 100;
	// 滑动效果类型
	private static Boolean mNormal = false;

	public FlingLayout(Context context, AttributeSet attrs) {
		this(context, attrs, 0);
		// TODO Auto-generated constructor stub
	}

	public FlingLayout(Context context) {
		this(context, null, 0);
		// TODO Auto-generated constructor stub
	}

	public FlingLayout(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		// TODO Auto-generated constructor stub
		mScroller = new Scroller(context);

		mCurScreen = mDefaultScreen;
		mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
		Log.i(TAG, "ScrollLayout" + mTouchSlop);

		mCamera = new Camera();
		mMatrix = new Matrix();
	}

	public void setHandler(Handler handler) {
		this.mHandler = handler;
	}

	public static void setNormal(boolean normal) {
		mNormal = normal;
	}

	/*
	 * 
	 * 为子View指定位置
	 */
	@Override
	protected void onLayout(boolean changed, int l, int t, int r, int b) {
		// TODO Auto-generated method stub
		int childLeft = 0;
		final int childCount = getChildCount();

		for (int i = 0; i < childCount; i++) {
			final View childView = getChildAt(i);
			if (childView.getVisibility() != View.GONE) {
				final int childWidth = childView.getMeasuredWidth();
				childView.layout(childLeft, 0, childLeft + childWidth,
						childView.getMeasuredHeight());
				childLeft += childWidth;
			}
		}
		Log.i(TAG, "onLayout-childCount:" + childCount);
	}

	// 重写此方法用来计算高度和宽度
	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		super.onMeasure(widthMeasureSpec, heightMeasureSpec);

		final int width = MeasureSpec.getSize(widthMeasureSpec);
		final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
		if (widthMode != MeasureSpec.EXACTLY) {
			throw new IllegalStateException(
					"ScrollLayout only canmCurScreen run at EXACTLY mode!");
		}

		final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
		if (heightMode != MeasureSpec.EXACTLY) {
			throw new IllegalStateException(
					"ScrollLayout only can run at EXACTLY mode!");
		}

		// The children are given the same width and height as the scrollLayout
		final int count = getChildCount();
		for (int i = 0; i < count; i++) {
			getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec);
		}
		Log.d(TAG, "moving to screen " + mCurScreen);
		scrollTo(mCurScreen * width, 0);
	}

	/*
	 * 当进行View滑动时，会导致当前的View无效，该函数的作用是对View进行重新绘制 调用drawScreen函数
	 */
	protected void dispatchDraw(Canvas canvas) {
		// TODO Auto-generated method stub
		if (!mNormal) {
			final long drawingTime = getDrawingTime();
			final int count = getChildCount();
			for (int i = 0; i < count; i++) {
				drawScreen(canvas, i, drawingTime);
			}
		} else {
			super.dispatchDraw(canvas);
		}
	}

	/*
	 * 立体效果的实现函数 ,screen为哪一个子View
	 */
	public void drawScreen(Canvas canvas, int screen, long drawingTime) {
		// 得到当前子View的宽度
		final int width = getWidth();
		final int scrollWidth = screen * width;
		final int scrollX = this.getScrollX();
		if (scrollWidth > scrollX + width || scrollWidth + width < scrollX) {
			return;
		}
		final View child = getChildAt(screen);
		final int faceIndex = screen;
		final float currentDegree = getScrollX() * (angle / getMeasuredWidth());
//		System.out.println("getMeasuredWidth---->" + getMeasuredWidth()
//				+ "getScrollX()----->" + getScrollX() + "currentDegree--->"
//				+ currentDegree);
		final float faceDegree = currentDegree - faceIndex * angle;
		if (faceDegree > 90 || faceDegree < -90) {
			return;
		}
		final float centerX = (scrollWidth < scrollX) ? scrollWidth + width
				: scrollWidth;
		final float centerY = getHeight() / 2;
		final Camera camera = mCamera;
		final Matrix matrix = mMatrix;
		canvas.save();
		camera.save();
		camera.rotateY(-faceDegree);
		camera.getMatrix(matrix);
		camera.restore();
		matrix.preTranslate(-centerX, -centerY);
		matrix.postTranslate(centerX, centerY);
		canvas.concat(matrix);
		drawChild(canvas, child, drawingTime);
		canvas.restore();
	}

	/**
	 * 根据目前的位置滚动到下一个视图位置.
	 */
	public void snapToDestination() {
		Log.i(TAG, "snapToDestination");
		final int screenWidth = getWidth();
		final int destScreen = (getScrollX() + screenWidth / 2) / screenWidth;
		snapToScreen(destScreen);
	}

	public void snapToScreen(int whichScreen) {
		Log.i(TAG, "snapToScreen"+whichScreen);
		// get the valid(有效的) layout page
		whichScreen = Math.max(0, Math.min(whichScreen, getChildCount() - 1));
		if (getScrollX() != (whichScreen * getWidth())) {

			final int delta = whichScreen * getWidth() - getScrollX();
			mScroller.startScroll(getScrollX(), 0, delta, 0,
					Math.abs(delta) * 2);
			mCurScreen = whichScreen;
			invalidate(); // 重新布局
		}
		if (mHandler != null) {
			mHandler.sendEmptyMessage(whichScreen);
		}
	}

	public void setToScreen(int whichScreen) {
		whichScreen = Math.max(0, Math.min(whichScreen, getChildCount() - 1));
		mCurScreen = whichScreen;
		if (!mScroller.isFinished()) {
			mScroller.abortAnimation(); // 终止Animation
		}
		scrollTo(whichScreen * getWidth(), 0);
	}

	public int getCurScreen() {
		return mCurScreen;
	}

	@Override
	public void computeScroll() {
		// TODO Auto-generated method stub
		if (mScroller.computeScrollOffset()) {
			scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
			postInvalidate();
		}
	}

	@Override
	public boolean onTouchEvent(MotionEvent event) {
		// TODO Auto-generated method stub

		if (mVelocityTracker == null) {
			mVelocityTracker = VelocityTracker.obtain();
		}
		mVelocityTracker.addMovement(event);

		final int action = event.getAction();
		final float x = event.getX();
		final float y = event.getY();

		switch (action) {
		case MotionEvent.ACTION_DOWN:
			Log.i(TAG, "event down!");
			if (!mScroller.isFinished()) {
				mScroller.abortAnimation(); // 终止Animation
			}
			mLastMotionX = x;
			break;

		case MotionEvent.ACTION_MOVE:
			int deltaX = (int) (mLastMotionX - x);
			mLastMotionX = x;

			scrollBy(deltaX, 0);
			break;

		case MotionEvent.ACTION_UP:
			Log.i(TAG, "event : up");
			// if (mTouchState == TOUCH_STATE_SCROLLING) {
			final VelocityTracker velocityTracker = mVelocityTracker;
			velocityTracker.computeCurrentVelocity(1000);
			int velocityX = (int) velocityTracker.getXVelocity();
			Log.i(TAG, "velocityX:" + velocityX);

			if (velocityX > SNAP_VELOCITY && mCurScreen > 0) {
				// Fling enough to move left
				Log.i(TAG, "snap left");
				snapToScreen(mCurScreen - 1);
			} else if (velocityX < -SNAP_VELOCITY
					&& mCurScreen < getChildCount() - 1) {
				// Fling enough to move right
				Log.i(TAG, "snap right");
				snapToScreen(mCurScreen + 1);
			} else {
				snapToDestination();
			}
			if (mVelocityTracker != null) {
				mVelocityTracker.recycle();
				mVelocityTracker = null;
			}
			// }
			mTouchState = TOUCH_STATE_REST;
			break;
		case MotionEvent.ACTION_CANCEL:
			mTouchState = TOUCH_STATE_REST;
			break;
		}

		return true;
	}

	@Override
	public boolean onInterceptTouchEvent(MotionEvent ev) {
		// TODO Auto-generated method stub
		Log.i(TAG, "onInterceptTouchEvent-slop:" + mTouchSlop);

		final int action = ev.getAction();
		if ((action == MotionEvent.ACTION_MOVE)
				&& (mTouchState != TOUCH_STATE_REST)) {
			return true;
		}

		final float x = ev.getX();
		final float y = ev.getY();

		switch (action) {
		case MotionEvent.ACTION_MOVE:
			final int xDiff = (int) Math.abs(mLastMotionX - x);
			if (xDiff > mTouchSlop) {
				mTouchState = TOUCH_STATE_SCROLLING;

			}
			break;

		case MotionEvent.ACTION_DOWN:
			mLastMotionX = x;
			mLastMotionY = y;
			mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST
					: TOUCH_STATE_SCROLLING;
			break;

		case MotionEvent.ACTION_CANCEL:
		case MotionEvent.ACTION_UP:
			mTouchState = TOUCH_STATE_REST;
			break;
		}

		return mTouchState != TOUCH_STATE_REST;
	}

}